Sealed telescopic pipe joint



Aug 4, 1953 o. E. 'roLLEFsBoL 2,647,770

i SEALED TELESCOPIC PIPE JOINT Filed 001'.. 4, 1950 TTOPNE'Y Patented Aug. 4, 1953 "SEALED TELEscoPIc PIPE JOINT Orion E. Tollefsbol, Oak Ridge, Tenn., assignor tothe United States of America as represented by the United States Atomic Energy Commission Application October 4, 1950, Serial No. 188,437

This invention relates to sealed telescopic pipe joints and metallic gaskets therefor, and it is particularly concerned with apparatus of this nature which is especially adapted to operate under extremely rigorous conditions of temperature and pressure.

The present invention has particular utility inconnection with the common problem of providing a flexible fluid tight interconnection between two aligned pipes or ducts. One approach to the solution of this problem involves terminating one of the pipes in a section having a larger internal diameter than, the outer diameter of the other pipe, telescoping the enlarged section about the smaller pipe, and inserting a` hollow metallic ring gasket in the annular 'space formed between the two pipes. V

The hollow metallic ring gaskets heretofore employedfor this purpose have been fabricated of a deformable non-resilient metal, such as soft copper, and they have beensymmetrical with rel spect to a transverse plane. Suchgaskets have` not proved entirely satisfactory for use under extremely high temperature conditions involving substantial diilerential expansion between "the ring gasket and the joined pipes. It will be apparent that under such conditions undesirable hoop stresses are set up in the gasket bylthe ex` pansion and contraction of the surrounding pipes. Furthermore, in order for the gasket to accommodate itself to the varying pipe diameter, the actualcross section of the-hollow tubing from which the gasket is formed must also vary, and this, in turn, varies the packing; pressure and may cause the gasket to leak. In other words, under stringent conditions, the tubing may have to elongate itself to such an extent that its diameter may actually become less than the space between the telescoped pipes, under which conditions of course, it is no longer effective as a gasket.

Accordingly, an object of the present invention is to provide a flexible sealed joint adapted to remain fluid tight under extremely high operating temperatures.

Another object of the present invention is to provide a hollow metallic ring gasket adapted to accommodate itself to varying diameters without the simultaneous introduction of hoop stress and without simultaneous variation in diameter of the gasket tubing.

Applicant has conceived that the above objects may be accomplished by fabricating the hollow ring gasket of a resilient metal, rather than a non-resilient metal, and b y forming the "3 claims. (01.285-163) ring gasket so as to be non-symmetrical vwith Thus, in`

respect to a median transverse plane. accordance with the principles of the present invention, applicant forms his gasket such that it oscillates axially of the pipes as it travels around the circumference of the inner pipe. In this manner, forced variations in the diameter of the gasket, resulting from expansion and contraction of the `associated pipes, are taken up by variations in the magnitude of the axial oscillations,

and thus no undesirable hoop stresses or varil ations in the diameter of the tubing result.

Other objects and advantages of the present inventionwill become apparent from the following detailed description when taken in connection with the accompanying drawings-wherein Fig. lis an elevation View, partially broken away. of one embodiment of a sealed joint con- I structed according to the principles of the present invention.y

Fig. 2 is a perspectiveview of the novel gasket employed in the sealed joint of Fig. 1.

Fig. 3 is a cross section of the tubing from which the gasket of Fig. 2` is fabricated.

Fig. 4 is a cross section of a modified form of tubing which may be used to fabricate the gasket of Fig. 2. l I

Referring now to the drawings, the two pipes which are to be joined in' a fluid tight flexible relationship are designated at I and 2, respectively, the 'inner diameter of at least the end sec-l tion of pipe 2 being largerthan the outer diameter of pipe I. The outer surface of the extremity of pipe I is tapered somewhat, as indicated at 8. Thetwo pipes are arranged in telescoped vrelationship, that is, the end of pipe I is inserted within pipe 2 thereby forming an annular space 3 between the pipes. An annular groove or recess 4 is cut in the inner surface of pipe 2 near the end of the pipe.

Within the recess 4 is disposed the sealing gasket 6 which is formed of a continuous length of hollow tubing fabricated of a resilient metallic material, such as a spring steel or Monel metal. The hollow tubing, when uncompressed, may have either an O-shaped cross section, as shown in Fig. 3, or a C-shaped cross section, as shown in Fig. 4, the latter being preferred. The gasket 6 is circular, when viewed axially of the pipes, so as to conform to the circular cross section of the pipes. However, in its traverse around the circumference of pipe I, the tubing Zig-zags axially of the pipe. Thus, when viewed perpendicularly to the axis of the pipes, the gasket presents a generally sinusoidal or serpentine contour resulting from the axial excursions of the tubing from a median transverse plane.

Since the tubing is fabricated of a resilient metal, it will be apparent that the gasket, itself, will have some normal (undeected) diameter, and that its diameter may be made to vary in either direction from its normal" valueby `spring action, the'variati'on ineffective circumference being accommodated by an inverse variation inA the amplitude of the axial excursions about its? rlhus, neither-normal:-

median transverse plane. (undelected) contour of the gasket is Yas shown in Fig. 2, it will be clear that!thedgasketlmayjbe sprung apart so as to increase5itsiiiarrieter'A dl decrease the amplitude of the"axial exc'usions'm or the gasket may be compressed so as to decrease its diameter and increase theamplitude mfr-the".

axial excursions. It will also be appreciated, that,

such variations in diameter of the gasketiill not result in any change in the cross section of not limited to use in association with round pipes. The gasket 6 could be fabricated to have any desired shape when Viewed along the pipes, for example, a hexagonal shape if it is to be used in association with hexagonal pipes.

Since many changes could be made in the abovelconstnuctiorr` and many apparently widely differenteinb'odim'ents ofthis'invention could be v,njiade Without departing from the principles fthereof, it is intended that all matter contained im thegaboyeedescription, or shown in the accomings, shall be interpreted as illustinaliniting sense. aimedfis;

1"."'A "saled joint-.bf the character described, comprising, in combination, a rst tube, a second tuheriofflargenidiameter telescoped about said first panying draw vtubetonfdrm an annular space therebetween, and

" a continuous, ring-like, hollow, resilient, metallic thef-tubing'nor in thel'introductiorr ofmtdesirable hoo'pistresses:v in the tubing,

I'n assembling thefsea'ledijoint-showninflig: I1', the gasket is rst compressed! and insertedinthe end- 'opip 2 andfisthempermittedzto .springfmtof thef'recess fig-the gasket being`=initiallyfabniafted to' have axnorin'al'. '(undeii'ectedlfouterf diameten somewhatgreater thanthe ydi'ameteriof,:tharecess d softhat'thei gasket will bei'securelylreftained'in therrecessiby its-ownlsprng-faction. Thelendrof-f.

I is then .forcedinto the positionf'shownfinrFig11, the I taper 82 at "the f endt fof? pipe. l1 gradually compressing the'` gaskettubingf-into. af'sorn'ewhatovali crossisectionias shown.iniig.;.l.

It Wil'lfbe` apparentth'at by.' virtue ofthe-:atbove-- described springy laction ofi'thegasket, the.' iiexiv ble sealedf joint :of the-presenttinvention wfi1lre'. main 'gas f tight firrespective.' off fanyL-differential expansion which may occur between theizgzevsket.V

andthe associated 'elements ,offthefjoinu the gas.- ket being capable" off'adjusting y#itself-5 .tof-'any changes indiameteri which the pipes may experi'.-

ence. change: in the 'cross fsectionof:4 the'fgasket. tubing, the packing pressure of; the tubingiis notv altered. nor are any hoop stress introduced in the tubjngi. The sealed' joint of: the present'` invention'isfthus of; particular utility'` in applications'.involving'the` Since:v this 'I adjustment:Y occurs Without sea-ling: of high-pressure.fluids at highftempera-:vim

tures. It-Will also-'beappreciated;that:the*sealedf jointA of the: present invention is;adaptednztoffauf` commodate linear, rotary, andi some angular dise. placementbetween the .pipes tand-2;

VIt, should be. understood thai-, thef invention '-fisi-i gasket disposed in its entirety in the annular space".A b etweensaidtubes ,tot formi a seal therebetween','l`fthe.-normal uncompressed diameter" ofsaidL fgatsketibeingf vgreater than thedist-ance betvveenthe outer'surface--ofy said rst tube andythe inner-'surface of saidsecond 'tube' so vthat saidY gasket is compressed when so disposed inwsaid` annulaispacal'saidi gasket havingafserpentine coiitourY-formedf-by@ axialexcursionsv about Iits medianctransverseiplane; said gasket ibeing unrestrlainedi 'in` respect' 'to .-ex.pansion` and contractioninan axialvdirection,

:21 :.Apparatusn asclaimed in claim- 1, wherein said gasketk isformed *ofs hollow tubing Vhavingy an Oeshapedicross section.

13'.Apparatus'asfclairned-in claim l,y whereiny saidf. gasket.` has a G--shaped cross section.

ORION E. TOLLEFSBOL.

-Refexiencese-Gited inY thele of .this -patent 

